1. Field of the Invention
This invention relates to a digital processing system. The present invention may be applied to a digital recording and/or reproducing system. An aspect of the invention relates to the error compensating ability of such a system.
2. Related Background of Art
In recent years, digital recording and/or reproducing devices such as so called digital VTR have become widely used. One kind of digital VTR records segments by a method in which information for one TV frame is divided into several segments and these segments are recorded separately on several recording tracks of magnetic tape.
FIG. 2 shows an example of coded data for one such segment of TV frame information. In this example a double product coding which consists of an inner coding (n, m) and an outer coding (q, p) is executed. This kind of double product coding can be Reed-Solomon coding.
When reproducing this coded data, it is decoded and errors contained in the data are corrected using the error correction code if this is possible and if it is not possible to correct errors using the error correction code but an error is nevertheless detected, a compensation such as interpolation is executed by using data from information for an adjacent frame or for the same frame. However, the error rate in a transmission system such as a digital VTR may vary over a wide range and if the error rate is very high, improper correction of the errors may be carried out.
Since the prior digital VTR compensates decoded data depending on the result of the error correction, if improper error correction is carried out as mentioned above then the compensation may not be carried out when it should be, or may be carried out incorrectly or inappropriately. This compensation failure may cause serious damage in the reproduced image on a TV screen. In particular a burst error tends to occur for a relatively long period in a special effect reproducing mode of a VTR. So, unless the correction ability is greatly improved, a high quality image in special effect reproduction cannot be obtained.